Nontarnishing compositions



United States Patent Ofiice 2,848,419 Patented Aug. 19, 1958 2,848,419 NONTARNISHING COMPOSITIONS Louis H. Libby, Flossnu'o'or, Ill., assignor to Lever Brothers Company, New York, N. Y., a corporation of Maine No Drawing. Application July 12, 1954 Serial No. 442,893

20 Claims. (Cl. 252-437) This invention relates to cleaning compositions containing tarnish inhibitors and more particularly to polyphosphate and synthetic detergent compositions containing guanide compounds as tarnish inhibitors.

Compositions containing polyphosphates and/or synthetic detergents are now widely used for detergent and other purposes. Aqueous solutions of polyphosphates and some synthetic detergents tend when at certain pH values to tarnish copper, and certain alloys containing copper such as German silver (a nickel-zinc-copper alloy) to a variety of shades from yellow to bluish black, especially if the solutions are at elevated temperatures and are allowed to remain in contact with the metal for several minutes. Since German silver is frequently'used for household articles commonly washed in polyphosphatebuilt detergent compositions, it is evident that this is a serious problem.

In accordance with the instant invention polyphosphate and detergent compositions are provided containing a tarnish inhibitor which compositions will not tarnish copper, and certain alloys containing copper such as German silver. The tarnish inhibitor of the invention is a guanide which is described by the following formula:

At least one of R R and R is a saturated or unsaturated aliphatic or aromatic hydrocarbon or chlorinated hydrocarbon radical or a heterocyclic radical and can be selected from the group consisting of aliphatic, aryl, mixed alkylene aryl, mixed phenylene heterocyclic and mixed alkylene heterocyclic radicals, and the other R radicals can be hydrogen or any of the radicals selected from the above-mentioned group. When R R and/or R is an aliphatic radical it can have either a straight or branched chain.

The number of carbon atoms in the R group is important. Acetoguanide is not very effective. Good tarnish-inhibiting properties appear when at least one of R R and R is a radical having three carbon atoms and the remaining R groups are hydrogen, but relatively large amounts of guanide may be necessary for complete protection. Tarnish-inhibiting ability materially improves as the R groups increase further in molecular weight,

2 and lesser amounts can be used. However, the solubility of the higher g'uanides is low and tarnish-inhibiting properties decrease for this reason. I,

Optimum tarnish-inhibiting properties are displayed by compounds in which at least one R group has trom seven to seventeen carbon atoms. Typical R radi'cals are straight andbranched chain propyl, butyl, hexyl, pentyl, heptyl, octyl, nonyl, decyl, hendecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, decenyl, heptylenyl, hexadecyl, h'eptadecyl, dcynyl, dodecenyl, heptadecenyl, the mixed alkyl radicals derived from fatty oils such as palm oil, rapeseed oil, tall oil, linseed oil, chlorinated palm kernel fatty acids, phenyl, b'enzyl, phenyl guanidyl, decylene guanidyl and octylene guanidyl.

These guanides are in many instances known compounds and are readilly prepared by reaction of the corresponding dicyandiamide and the corresponding acid 1) using a monocarboxylic acid in a 1:1 molar ratio if one guanide radical is to be present and (2) using a dicarboxylic acid in a 2:1 molar ratio iftwo guanide radicals are to be present. See also U. S. Patent No. 2,431,644, dated November 25, 1947, to Kaiser. The reaction proceeds in accordance with the following equations:

(I: NH N/ N nloo'on Nrnntii-Nnon N'rnRz-ii d-OH H20 (2) NH nooonsooon 2NR1R2 i 1NHCN on OH til-N N-ir N C-Rfi-O N 211.0

At the same time, approximately equal amounts of the amide of the acid are formed.

The mixture of the acid and dicyandiamide is heated at an elevated temperature, say 180 C., for several hours. Temperature from to 250 C. have been found satisfactory.

The crude mixture which is obtained as a result of this reaction can be used without further purification and consists mainly of the substituted guanide and the amide of the acid starting material in approximately equal amounts. The guanide has been isolated and shown to be the principal antitarnishing constituent of the mixture.

The guanides in accordance with the invention are nontoxic, sparingly water-soluble substances, but sufliciently water-soluble to permit their incorporation in polyphosphate and synthetic detergent solutions in the amounts required to impart tarnish inhibition thereto. v

An amount of the guanide would be added to the polyphosphate and/or synthetic detergent composition sufiicient to give tarnish inhibition when the composition is used in its normal way. Usually about 0.1%

of the guanide gives adequate tarnish inhibition, but larger amounts can be used if desired. From 0.1 to is effective under nearly all conditions and therefore is preferred. The maximum amount of guanide is not critical but more than is necessary to give the desired effect usually would not be used, and of course an amount in excess of that soluble in the solution would not be used. It will be understood that the amount required will depend in part upon the tarnish-inhibiting properties of the particular guanide in question, upon the tendency of the polyphosphate and/or synthetic detergent with which it is used to tarnish copper, and certain alloys containing copper, and upon the amounts of polyphosphate and synthetic detergent present.

The guanides of the invention are efiective as tarnish inhibitors in both hard and soft water.

The tarnish inhibitors of the invention are effective with water-soluble polyphosphates as a class at pH values where such polyphosphates tend to tarnish German silver (usually pH 6 or above) and particularly those polyphosphates identified by the following general formula from which it is seen that both the acids and their various salts are contemplated:

[(M M M PO minus b( MOM) l,

where M M and M are hydrogen or an alkali metal, such as sodium, potassium and ammonium, and can be the same or different, and M is M and/ or M and/or M a is an integer of l or more, usually 1 to 4,

b is an integer of 1 or more, usually 1 or 2,

x is an integer of 1 or more, usually 1 to 6.

In the case Where a is 2, b is 1 and x is 1, the compound is a pyrophosphate. When a is 1, b is 1 and x is 1, the compound is a metaphosphate. Others will be evident to those skilled in the art.

The upper limit of a, b and x is not critical, but will be determined by the increasingly lower water-solubility as molecular weight increases. The sodium polyphosphates are preferred.

As the general formula shows, both the normal and acid salts of the phosphates are within the scope of the invention.

Among the polyphosphoric acids and their alkali metal salts coming within the invention are the polymetaphosphoric acids (HPO (a is 1, b is 1, x is more than 1), pyrophosphoric acid H4P3O7 (a is 2, b is 1, x is 1), triphosphoric acid H P O (a is 3, b is 2, x is 1), and tetraphosphoric acid H P O (a is 4, b is 3, x is 1). s s m K4P2O'7: a z r z z z 'z, s 4 13 dium Polyphos (Na P O Blockson) Pascals salt, sodium dimetaphosphate, sodium trimeta phosphate (Knorres salt), sodium tetrametaphosphate and sodium hexametaphosphate (Graharns salt) are examples.

The guanide tarnish inhibitors can be incorporated in compositions containing polyphosphates, and in compositions containing synthetic detergents, and are effective to reduce tarnish due to polyphosphate or detergent in each of these types of compositions. They are particularly useful in synthetic detergent compositions which contain one or more polyphosphates as builders and one or more synthetic detergents, i. e., anionic, cationic and nonionic detergents, and mixtures thereof. In many instances they display an enhanced tarnish-inhibiting action in the presence of both polyphosphate and detergent.

The polyphosphate-built detergent compositions should contain conventional proportions of active detergent, usually within the range between 5 to 40%, polyphosphate 4 in any amount, usually between 5 to 50%, based on the total composition, and the residue builders and inert materials.

The guanides arse useful with a wide variety of anionic, cationic and nonionic synthetic detergents, with and without polyphosphates.

The alkyl aryl sulfonates are a class of detergents well known in the art under this name. One example thereof are the sulfonated phenylpolypropylene alkanes, characterized by the branched chain structure of polypropylene and a tertiary alkyl carbon at the benzene ring, and having the following general structure:

SOaM

where M is hydrogen, an alkali metal or an organic amine cation, and R and R are alkyl, of the type formula C H and at least one R is a polypropylene group, the Whole alkyl group containing preferably twelve to fifteen carbon atoms. These are known compounds, whose preparation and properties are set forth in U. S. Patent No. 2,477,383 to Lewis, issued July 26, 1949; they are available in commerce under the trade names Oro nite, Ultrawet and Neolene.

Another class of useful detergents are the amidoalkane sulfonates which are characterized by the following structure:

where A is hydrogen or an alkali metal, i. e., ammonium, sodium, or potassium, n is a small whole number from one to about five, preferably two or three, R is hydrogen, or an alkyl, aryl, or cycloaliphatic group, such as methyl, and R is an alkyl or alkylene radical, such as myristyl, palmityl, oleyl and stearyl. Sodium palmitic tauride, sodium palmitic methyl tauride, sodium myristic methyl tauride, sodium palmitic-stearic methyl tauride and sodium palmitic methyl amidopropane sulfonate have been found to be particularly suitable for use in the compositions of the invention.

These compounds are prepared by interacting the corresponding aliphatic acid anhydride or halide with an organic aliphatic aminosulfonic acid, such as taurine, NH CH CH SO H, and the various N-substituted taurines, such as N-methyl taurine, or aminopropane sulfonic acid, NH2(CH2)3SO3H.

The invention is also applicable to other water-soluble alkyl aromatic sulfonic acids, such as those prepared by alkylating benzene or naphthalene with a kerosene fraction followed by sulfonation to aliphatic sulfonic acids, esters of sulfuric acid with aliphatic alcohols of ten to eighteen carbon atoms, particularly those derived by the reduction of coconut oil, palm oil and like long-chain fatty acids, sulfonated castor oil, esters and ethers of isethionic acid, long-chain fatty acid esters and long-chain alkyl ethers of 2,3-dihydroxy propane sulfonic acid and sulfuric acid esters of monoglycerides and glycerol mono ethers. The salts of these acids are ordinarily employed.

The tarnish inhibitors are also useful with nonionic detergents, such as, for example, alkyl oxyether and ester and thioether and ester detergents having the following formula:

Where R is a sn'aight or branched chain saturated or unsaturated hydrocarbon group having from eight to eighteen carbon atoms or an aralkyl group having a straight or branched saturated or unsaturated hydrocarbon group of from eight to eighteen carbon atoms attached to the aryl nucleus, and attached to A through the aryl nucleus, A is selected from the group consisting of ethereal oxygen and sulfur, carboxylic ester and thiocarboxylic ester, amino NH- and carbonamido -CONH- groups and x is a number from eight to twenty. R can, for example, be a straight or branched chain octyl, nonyl, decyl, lauryl, myristyl, cetyl or stearyl group, or an alkyl aryl group such as octylbenzene, nonylbenzene, decylbenzene, stearylbenzene, etc.

The sulfated oxyethylated derivatives of the above also are useful anionic detergents:

where M is hydrogen or an alkali metal or organic amine cation and x, A and R are as above.

When R is alkyl it will be evident that the detergent can be regarded as derived from an alcohol, mercaptan, oxy or thio fatty acid of high molecular weight, by condensation with ethylene oxide. Typical of this type of alkyl ether are the condensation products of oleyl or dodecyl alcohol or mercaptan with from eight to seventeen moles of ethylene oxide, such as Emulfor ON, Nonic 218 and Sterox SE and SK. Typical alkyl esters are G1226 and Renex (polyoxyethylene ester of tall oil acids), Sterox CD and Neutronyx 330 and 331 (higher fatty acid esters of polyethylene glycol).

When R is aralkyl, the detergent can be derived from an alkyl phenol or thiophenol.

The oxyethylated alkyl phenols and thiophenols have .the following general formula:

where R is a straight or branched saturated or unsaturated hydrocarbon group having at least eight carbon atoms up to approximately eighteen carbon atoms, A is oxygen or sulfur and x is a number from eight to twenty. R can, for example, be a straight or branched chain octyl, nonyl, decyl, lauryl, cetyl, myristyl or stearyl group. Typical are the condensation products of octyl and nonyl phenol and thiophenol with from eight to seventeen moles of ethylene oxide, available commercially under the trade names NIW, Antarox A-400, 'Igepal CA and C0, Triton X-l00, Neutronyx 600 and Tergitol NFX.

The detergent composition can contain supplemental builders including alkali metal and alkaline earth metal sulfates, chlorides, silicates, borates, carbonates, metaphosphates, and orthophosphates, such as sodium silicate, magnesium sulfate, sodium tetraborate, sodium carbonate, sodium sulfate, trisodium phosphate, potassium carbonate, disodium orthophosphate, sodium metaphosphate, calcium sulfate, calcium chloride, sodium chloride, sodium borate and potassium metaphosphate. The builder should but need not be water-soluble.

In addition to or instead of the above-mentioned supplemental inorganic salts, organic materials such as starch, polyethylene glycols, polyvinyl alcohols and salts of carboxylmethylcellulose can be used as builders. It has been found that between about 0.1 and 1% of an alkali metal carboxymethylcellulose increases detergency and sudsing.

The builder mixture is so chosen among alkaline, neutral and acidic salts that the composition obtained in an aqueous 0.14% washing solution has a pH of 7 or above. Preferably, its pH lies within the range from 8 7 to about 10 since solutions which are more alkaline may be irritating to the skin and tend to weaken some fabrics, particularly woolens. In general, the alkali metal carbonates are preferred agents for bringing the pH of the solution to a high alkaline value within the preferred range.

The detergent composition is prepared by conventional methods, as by blending the ingredients thereof in an aqueous solution or slurry and then drying the resulting mixture in a spray or drum dryer at elevated temperatures.

The tarnish inhibitor may be added to the polyphosphate or detergent composition at any stage of its manufacture, to the finished polyphosphate or detergent composition, or to the polyphosphate or detergent solution.

The guanides employed in the following examples were prepared by heating mixtures of dicyandiamide and the corresponding acid at 185 C. for about two and onehalf hours. In the case of monocarboxylic acids 1:1 molar ratios were taken of dicyandiamide and the acid and in the case of dicarboxylic acids 1:2 molar ratios of the acid to the dicyandiamide were taken, thus resulting in products containing one and two guanide radicals, respectively. The crude product was used unless otherwise indicated.

Compositions in the examples were tested for tarnish inhibition in accordance with the following test: German silver dessert spoons were selected from a batch known to be susceptible to attack and the same six spoons used for all groups of detergents tested in the same formulation. The spoons were prepared by polishing with a good silver polish and scrubbed with a brush using a cold, slightly alkaline solution of sodium lauryl sulfate. The spoons were then partially immersed in ml. of an aqueous solution (hard or soft water) of the formulation being tested and held at 70 C. until tarnish was observed (usually grades 3, 4 or 5), or up to a maximum of sixty minutes, whichever time was the shorter, after which the spoons were rinsed and wiped. At the conclusion of the test, the spoons were assigned a grade number by comparison with a standard graded series of eighteen spoons showing different degrees of tarnish, divided into six lots of three spoons each and graded as follows:

Acceptability is based on the sixty minute test only. Grades 0 and l are acceptable and grades 2 and 3 are on the borderline, but acceptable if reached only after a time of sixty minutes. Grades 4 and 5 are unacceptable.

EXAMPLES 1 TO 22 A detergent powder was prepared having the followin g formulation:

Parts by weight Commercial sodium dodecyl (tetrapropylene polymer) benzene sulfonate 20 Tetrasodium pyrophosphate and pentasodium tripolyphosphate 32.5 Sodium sulfate and water 47.5

This composition was'dissolved in water to form a 0.4% solution. To this solution was added the amount of antitarnishing agent given in the table below, and the solution then was tested for tarnish inhibition by the above test, with the results noted in the table:

Table 1 Appearance of Degree Spoons Example No. and R9 Radical oi Guanlde 1 Percent Hardness 1 Guanidc of Water Used Minutes Grade Control I None Distilled 3 3 Control TT None 4 6 1 5 Control TIT None 24 60 3 1. Methyl. 2.0 Distilled 3 4 2. Methyl (purified) 2. 0 4 Q 2- 3. 0. 5 4 60 i 4. 2. o 4 $8 6. 0.2 4 60 1 6. 0.2 24 60 2-3 7. 0. 5 4 60 0 8. 0. 6 24 0-1 9. 0. 2 4 0 10. 0. 2 24 60 0-1 11. Hendecyl 0.5 24 60 0 12. Mixed alkyl from palm oil fatty acids 0.2 4 60 0-1 13. Mixed alkyl from palm oil fatty acids. 0.2 24 60 2-3 14. Mixed alkyl from palm oil fatty acids, 0. 5 24 60 0 15. Heptadecyl 1.0 4 60 1-2 16. Mixed Allryl from hardened rapeseed oil fatty acids 1. 0 4 60 0 17. Alkyl derived from tall oil fatty acids (purified)... 0.8 Distilled 60 0 18. Phenyl 1.0 4 60 1 OH OH 5 C-N N- 9 N C 0 1 N 2.0 4 30 3 5 I NH: NH: (])H ()H CN N-C' 20. N CCH2CH-C N 1. 0 4 30 I 5 I N H; NH,

(|)H (IJH CN N-C 21 N C(CH2)aC /N 1. 0 4 60 01 C=N 1\=(|J NH: NH:

()H OH C-N N- 22. N\ /C- C\ /N 1.0 4 60 1-2 (IF- N N=C NH: NH:

1 See general formula in column 1. 1 if hardness=1 port (32100: per 100,000 parts water. Unacceptable.

It is evident from Examples 1 to 4 that compounds in which the alkyl group is less than three carbon atoms are unsatisfactory tarnish inhibitors. Butyroguanide is on the threshhold of tarnish-inhibiting activity since it is only acceptable at a relatively high concentration. Capryloguanide (Examples 5 to 8) gives good tarnish protection even at a 0.2% level for sixty minutes and is rated as acceptable under the above test. Lauroguanidc and higher mixed fatty alkyl guanides having eleven to seventeen carbon atoms in the alkyl radical are fully satisfactory (Examples 9 to 17, inclusive).

Example 18 shows that a phenyl radical is approximately the equivalent of seven CH units. A benzyl radical also is effective.

Example 19 shows that another guanide radical is not very etIective, and likewise, an w-guanidyl ethylene radical, succinoguanide, Example 20, is not efiective. Extension of the ethylene radical to eight CH units, sebaceguanide, Example 2l, materially assists tarnish inhibition and produces an excellent tarnish inhibitor. A phenylene radical is approximately the equivalent in activity of eight CH units, terephthaloguanide, Example 22.

From the above data it would be concludedthat alkyl radicals having from four to about seventeen carbon 75 njsapp -Qximately atoms, the phenyl radical, and a second guanide radical attached at the end of a higher alkylene chain or to a phenylene radical are eifective to render the guanide nucleus tarnish-inhibiting. Acetoguanide is not very eifective. EXAMPLES 23 to 30 A group of detergent compositions was made up as follows:

RCOOCZH4NHCOGH2SO3N8.

1 Lissapol N is an alkyl phenol (or cresol) condensed with ethylene oxide:

EGO-(C2H4MCHQCH2OH Appearance of Spoons Hardness of Water, degrees Percent Guanide Minutes Grade none 0.3 lauroguanide (purified) non 0.4 capryloguanide (purified).

Unacceptable.

Examples 23 and 24 show that the capryloguanide at a 0.4% concentration is effective to overcome the tarnishing due to tetrasodium pyrophosphate.

Examples 25 and 26 show that 1% of lauroguanide is effective to overcome the tarnishing due to a combination of sodium lauryl sulfate with'tetrasodium pyropho'sphate.

Examples 27 and 28 show that 0.3% of lauroguanide is efiective to overcome the tarnishing effect due to a combination of Ernco and tetrasodium pyrophosph'ate.

Examples 29 and 30 show that 0.4% capryloguanide is eifective to overcome the tarnishing effect due to Lissapol N and tetrasodium pyrophosphate in hard water.

EXAMPLE 3-1 Glassy phosphate .(Calgon) (20 parts), sodium dodecyl (tetrapropylene polymer) benzene sulfonate (20 parts) and sodium sulfate -(30 parts) were mixed together and dissolved in Water of 4 hardness to form a 0.4% solution. This solution was divided into two portions and to one portion was added 1% by weight of the detergent formulation of lauroguanide. Each solution was then tested for tarnishing properties by the above-described test with the following results:

Appearance of Spoons Percent Anti 'larnishlng Agent in Powder Minutes Grade Nil 10 1 1.0 lauroguanide 45 0 1 Unacceptable.

These results show that 1% lauroguanide is effective to overcome the tarnishing effect due to sodium hexametaphosphate in a detergent composition.

EXAMPLES 32 TO 34 The above formulations were made by mechanical mixing, and dissolved in water to form 0.25 and 0.5% solutions. The solutions were divided into two portions and to one portion of each was added purified capryloguanide in the amount of 1.5% by weight of the total phosphate in the composition. The results obtained were as follows:

Table 111 Ooncentra- Appearance of tion of Amount Spoons Example No. Powder of in the Guanide, Solution, percent Minutes Grade percent 0.50 none 15 1 5 32 0.50 1.5 60 0 0.25 none 15 l 5 0.25 1. 5 60 O 0. 50 none 60 1 5 33 0.50 1. 5 60 0-1 0.25 none -60 2-3 0525 l 1.5 60 0 34 0:50 none 60 1 0.50 V 1. 5 60 0 I Unacceptable.

The above results show purified capryloguanide to be an eife'ctive tarnish inhibitor at a 1.5% concentration. Compositions containing as little as 3% and 1% 'parts of the polyphosphates however show very little tarnishing action (Example 3 4).

EXAMPLE 35 Appearance of Spoons Percent Guanide Minutes Grade Nil 6 Unacceptable.

These results show that 0.1% of the purified capryloguanide is needed for good tarnish inhibition.

EXAMPLE 36 Table V Appearance of Spoons Percent Guanide Minutes Grade 1 Unacceptable.

These results show 0.1% purified capryloguanide is necessary-in the case of this formulation as well to obtain good tarnish-inhibiting action.

EXAMPLE 37 Table VII e Several of the alkyl guan des 1n accorda.uce with th Grading of spoons Hum Unless mvent1on have good suds-lmprovmg properties. The Stated Otherwise) following preparations demonstrate this: Exampl Material PH Lauroguanrde was combined wlth a commercial sodl- No. N G d .0335 um dodecyl benzene sulfonate detergent as indicated in the table below: Solution 7 ControL. Distilled water.... 0 Control Exampleli 38 0'05 NaPZ 01"" 0 842; a Commercial dodeeyl (tetrapropylene poly- Percent Percent 49 0 5 1 1 mer) benzene sulfonate 24.0 41 0.10% Qalgom 3 4 3 8 Laurie acid/dicyandiamide reaction product... N11 See table 42 LESSEPOI 6 0 Tetrasodium pyrophosphate and pentaso- 1115531101 -e dium tripolyphosphate 32. 5 32, 5 15 44 0.1% a. d 5. 6 5 ms.) Sodium sulfate, water and inert material. 43. 5 45. 5-47. 5

1 See Examples 23 to 30. Percent Z Teepol (see-alcohol sulfate) Aqueous solutions of the powders were prepared. The NH4 1 2.2 f 0 04 0 057 MgClz (crystals) 3.6 detergent was at a concentration 0 or a Sodium Gamma M active, convenuonal washing concentrations. 20 gegu z le 8.025

The solutions were tested by a standardized dlsha g gg washing test in which dinner plates were soiled with uniform amounts of tallow and then Washed with the solutions held at a temperature of 70 C. until lather was destroyed. The number of plates washed before destruction of lather was noted in the table:

Table VI The above results show that lauroguanide is efiective to inhibit tarnish due to various polyphosphates and detergents. The results for Examples 42 to 44 show that the presence of polyphosphate is not essential for tarnishing although the extent of attack is normally greater when the phosphate is present. The pH of the solution is a factor in the amount of tarnish experienced, but the lauroguanides tarnish-inhibiting action is not sensitive Number of Plates to H Washed P Amount of Laumgmmide The guamde employed in the following examples was 24: Hard 0 Soft prepared as follows: I I Water Water In a 5-liter flask w1th stirring four moles (820 g.) of 034% 005% distilled coconut oil fatty acids were reacted with four moles of dicyandiamide plus 5% excess (353 g.). The ZZZ materials were stirred and heated rapidly with a Bunsen burner. When the temperature of the mass reached 11 165 C., external heat was removed. The reaction at 40 that point was exothermic and, despite external cooling 14 the temperature went to 203 C. The product at that point was a white viscous material. The product was The above results show that in a concentration of 0.1% in soft water and in a concentration of 0.1% in hard water the lauroguanide gives a marked improvement in sudsing. At a 0.6% concentration in soft and hard water the suds volume is higher.

The reason for the suds-boosting effect in the lameguanide is not fully understood. The suds-boosting propallowed to cool to 180 C. and then removed from the flask. It is designated lauroguanide, although the other alkyl guanides obtained from coconut oil fatty acids of course were present.

EXAMPLES 45 TO 52 the Parts by weight Example 48 49 Na Orouite 1 Palmitie methyl tauride Myristic hydroxyethane sulf0nate Laurie hydroxyethane sulionate- Pentasodium tripolyphosphate Tetrasodium pyrophosphate.-- Sodium carboxymethyl cellulose Sodium silicate Lauroguanide l.

1 Sodium phenyl polypropylene sulfonate.

erties may be due to the lauramide rather than to the lauroguanide.

EXAMPLES 38 TO 44 A number of aqueous solutions of the following materials in the concentrations indicated in the table and having the pH set forth were prepared, with and without capryloguanide, and subjected to the standardized tarnishing test. The following results were obtained:

13 EXAMPLES 53 AND 54 A heavy duty powdered detergent was prepared by slurrying the ingredients named in the table below in water, adding the lauroguanide in the amount indicated and spray-drying:

Magnesium phenyl polypropylene sulfonate.

These formulations were tested for detergency and soil redeposition. The standard Terg-O-Torneter one wash detergency test was used. The indicated amount of the detergents was dissolved in 1250 cc. of 18 hard water to produce a washing solution. Each wash was carried out with 1250 cc. of washing solution at 120 F. at ninety complete oscillations per minute for twenty minutes. Eight soiled cotton swatches (vacuum cleaner dirt) and four unsoiled swatches were present in each wash. The average reflectometer reading of the soiled cloth after washing minus thirty is reported as detergent units and the diiference between the average reflectance readings of unsoiled cloths before and after washing is reported as redeposition units.

Example No 53 54 Detergent Units (0.14% concentration) The formulations were tested for sudsing power using the ABC washing test. Three ounces of the composition were dissolved in 16 gallons of water of and 30 hardness to give a 0.14% solution, and the solution used to wash standard soiled cloths in an ABC type household washing machine for twenty minutes at 125 F. with a cloth-to-water ratio of 1:16.

Sudsing power Example No 53 54 3 oz./16 gal.:

5 poor-Iain-.. fair. 30 excel1ent good.

These compositions in a 0.5% aqueous solution were tested for tarnish inhibition. Example 53 tarnished German silver whereas Example 54 did not. The composition containing the lauroguanide gave a greater suds volume in 5 water and had a higher detergency and a lower soil redeposition than the composition not containing the lauroguanide.

EXAMPLES 55 TO 58 A group of four detergent formulations was prepared. The ingredients named in the table below were mixed together mechanically:

Percent by'Weight Example No 55 56 57 58 Na Oronite 6 6 6 Palmitic methyl tauride 6 6 -6 6 Tetrasodiurn pyrophosphate 40 '40 40 Sodium sulfate 5 5 5 Sodium carbonate 6 5 5 Palmitic monoethanolamide Lauroguanide Lauroguanide reacted with o The compositions containing the lauroguanide do not tarnish German silver (Examples 56 to 58), whereas the composition of Example does.

EXAMPLES 59 TO 62 Four detergent formulations were prepared in which the ingredients named in the table below were mixed together mechanically:

Percent by Weight Mixed alkyl dimethyl benzyl quaternary ammonium chloride in which the alkyl is derived from coconut oil and has from eight to eighteen carbon atoms. I

These detergent formulations were dissolved in 50 p. p. in. water to form 0.4% solutions and to these solutions, in the cases of Examples and 62, were added 1% of lauroguanide. The solutions were tested for tarnish inhibition by immersing 1" x 6" German silver strips in the solution, which had been brought to C., and holding them at that temperature for one hour. The amount of tarnish was graded after twenty minutes and after one hour, and the extent of tarnishing is noted below:

Appearance of Strips moron) Nmwcn These results show that the lauroguanide is efiective to overcome the tarnishing eifect due to the tetrasodium pyrophosphate in the presence of cationic detergents.

Compositions containing tarnish inhibitors of the invention show little or no tendency to tarnish copper, and certain alloys containing copper such as German silver, coinage nickel or brass, which normally tarnish when exposed to aqueous solutions containing polyphosphates and/or synthetic detergents. It is not possible at this time to explain why :the compounds of the invention are efiective tarnish inhibitors.

Obviously, many modifications and variations may be made in the invention herein set forth without departing from the spirit and scope thereof, and only such limitations should be imposed as are indicated in the appended claims.

All parts and percentages in the specification and claims are by weight. Proportions of guanide are based on the weight of the tarnish-producing substance, i. e., polyphosphate and/or detergent, unless otherwise stated. In the examples, for ease of preparation, the weights From Acid R Radical Guanide acetoguanide. butyroguanide. capryloguanide. lauroguanide. stearcguanide. benzo guanide. terephthaloguanide. oxaloguanide.

succinoguanide.

sebacoguanide.

sebacic e.

I claim:

I. A detergent composition consisting essentially of a water-soluble substance selected from the group consisting of polyphosphates and synthetic organic nonsoap anionic and nonionic detergents which in aqueous solution tarnishes copper and certain alloys containing copper and a tarnish inhibitor in an amount to lessen the tarnishing action of the substance and having the general formula:

where R is an organic radical having at least three carbon atoms and selected from the group consisting of aliphatic hydrocarbon, aryl, mixed alkylene aryl, mixed phenylene guanide and mixed alkylene guanide radicals.

2. A detergent composition in accordance with claim 1 in which R has from seven to seventeen carbon atoms.

3. A detergent composition in accordance with claim 1 in which the tarnish inhibitor is lauroguanide.

4. A detergent composition in accordance with claim 1 in which the tarnish inhibitor is capryloguanide.

5. A detergent composition in accordance with claim 1 in which R is the mixed alkyl radicals derived from a naturally-occurring fatty oil.

6. A detergent composition in accordance with claim 1 in which the R radical is an aryl radical.

7. A detergent composition in accordance with claim 1 in which the R radical is a mixed alkylene guanide radical.

8. A detergent composition in accordance with claim 1 in which the R radical is a mixed phenylene guanide radical.

9. A detergent composition in accordance with claim 5 in which the fatty oil is palm oil.

10. A detergent composition in accordance with claim 5 in which the fatty oil is rapeseed oil.

11. A detergent composition in accordance with claim 5 in which the R radical is the mixed alkyl radicals derived from tall oil.

12..A detergent composition inaccordance with claim 6 in which the aryl radical is phenyl. v

13. A detergent composition consisting essentially of a water-soluble polyphosphate which in aqueous solution tarnishes copper and certain alloys containing copper and a tarnish inhibitor in an amount to lessen the tarnishing action of the substance and having the general formula:

where R is an organic radical having at least three carbon atoms and selected from the group consisting of aliphatic hydrocarbon, aryl, mixed alkylene aryl, mixed phenylene heterocyclic and mixed alkylene guanide radicals.

14. A detergent composition in accordance with claim 13 in which the amount of tarnish inhibitor is within the range from 0.5 to 5% by weight of the polyphosphate.

15. A detergent composition in accordance with claim 13 in which the polyphosphate is a tripolyphosphate.

16. A detergent composition in accordance with claim 13 in which the polyphosphate is a pyrophosphate.

17. A detergent composition in accordance with claim 13 in which the polyphosphate is a polymetaphosphate.

18. A detergent composition consisting essentially of a water-soluble synthetic organic nonsoap detergent selected from the group consisting of anionic and nonionic nonsoap detergents which in aqueous solution tarnishes copper and certain alloys containing copper and a tarnish inhibitor in an amount to lessen the tarnishing action of the detergent and having the general formula:

where R is an organic radical having at least three carbon atoms and selected from the group consisting of aliphatic hydrocarbon, aryl, mixed alkylene aryl, mixed phenylene heterocyclic and mixed alkylene guanide radicals.

References Cited in the file of this patent UNITED STATES PATENTS Schaefier Nov. 18, 1952 Schaeffer Nov. 18, 1952 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent Noo 2,848,419 August 19, 1958 Louis H Q Libby It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 2, line 16, for "readilly" read readily line 48, for "Temperature" read Temperatures column 4, lines 68 and 69, after "following" insert general column 16, lines 21 and 49, for

"heterocyclic", in each occurrence, read guanide Signed and sealed this 28th day offOctober 1958.,

(SEAL) Attest:

KARL H. AXLINE ROBERT (J. WATSON Resting ()flicer Commissioner of Patents 

1. A DETERGENT COMPOSITION CONSISTING ESSENTIALLY OF A WATER-SOLUBLE SUBSTANCE SELECTED FROM THE GROUP CONSISTING OF POLYPHOSPHATES AND SYNTHETIC ORGANIC NONSOAP ANIONIC AND NONIONIC DETERGENTS WHICH IN AQUEOUS SOLUTION TARNISHES COPPER AND CERTAIN ALLOYS CONTAINING COPPER AND A TARNISH INHIBITOR IN AN AMOUNT OF LESSEN THE TARNISHING ACTION OF THE SUBSTANCE AND HAVING THE GENERAL FORMULA: 